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The site was established when the violence of the civil war birth control pills 40 year old woman 3.03 mg yasmin otc, originally confined to the two largest ethnic groups in the country birth control coverage buy yasmin 3.03 mg amex, who were primarily pastoralists birth control ring purchase yasmin 3.03 mg otc, suddenly spread to Wau Town birth control for women 80 quality yasmin 3.03 mg. The residents of the city and farming environs fled to the United Nations Peacekeeping bases. The Protection of Civilian sites was originally an open space in which people were free to return to their businesses and fields during the day. Danger had increased and the residents could not leave during the day, as they were likely to be harmed. More than 21 ethnolinguistic groups were now residents of the Protection of Civilian sites. When newcomers arrived, speaking so many different languages, they often had no way to get information as to what services the camp could offer, how they could access them, and which camp organization could help, with anything from plastic sheeting to protect from rain to medical care or rations for children. The objective of the study was to learn about what was required to support the well-being of young men (under 35) and conflict-affected women, two groups most affected by the violence of the conflict. The study revealed that the Protection of Civilian sites had become a beacon for agriculturalists, people who stayed in one place, in a country largely inhabited by pastoralists. So even though languages, religion and ethnicities might be different among the residents, most shared lifestyles and values. The young men let the new arrivals know how they might access camp services, or connect to one of the camp management committees, which could then be more effectively representative. Engaging people used to using theatre allowed women and men to feel in control of their lives as they helped to stabilize the camp. With the course correction, the study yielded specific measurable and reportable indicators that could be refreshed or adjusted should the situation change again. The left-hand column of the chart should contain the domains that the participants have established and agreed upon. This will form the "baseline" against which the participants will measure the success of their programme going forward. Bring the chart to the midterm and final evaluation meeting, and fix it to an object so that it is easily visible. Point to the picture next to each domain and review the ways in which the group has operationalized it. After 6 months We have a meeting once a month where someone comes to bring us new information. We have visited the families at home and asked that husbands allow their wives to put in a coin. We have learned about conflict mediation in our group: we use this to support families. Are the actions they are taking really improving their sense of psychosocial wellbeing Following the evaluation, participants can plan the activities they would like to see continue as they move forward. These changes (sometimes called "course correction") should be reflected in the charts. The results of each monitoring exercise should be presented to all stakeholders at a community meeting. At the end of the programme, include the progress and changes recorded in the charts in the qualitative section of the final programme evaluation. These results should be widely distributed and, if possible, presented at a public learning conference so that the entire community can learn from successes and challenges, and create a community-owned way forward. The Community Participatory Evaluation Tool engages families, communities and children themselves to define and operationalize child well-being in a cultural context, based on age and stage of development. The process engages parents, elders, children and adolescents in discussing their cultural views of child well-being by age and stage of development. Participants are asked to discuss which practices from the past should be restored and which discarded as ineffective or harmful. The process often promotes social cohesion, as disparate groups in the community can unite for the benefit of their children. Bragin (2005c) includes a complete discussion of how to conduct the exercise, including model charts to use for monitoring, evaluation, accountability and learning. A member of the committee may be part of the group, unless there is a reason that he/she will be a hindrance to the decision-making process or other groups activities. Make sure that all sub-groups; children, youth, men, elderly (men and women), disability, religious, ethnic and political somehow are represented, but also social and sport clubs, community-based organisations. Individuals with technical expertise can be part of one of the groups or as technical advisors directly in the committee. Ensure that individuals become members of groups voluntarily and not under pressure from a third party. The group, it was decided, should be composed of two people per village, thus 32 people. Village leaders then returned to their villages and appointed two people to participate in the group who they felt showed potential and interest in participating in such a group. Although the volunteer concept had been discussed and agreed upon with village leaders and the group of games facilitators, the manner in which the group was selected did not reflect this principle and thus the expectation of compensation persisted. This is an asset to the project as these organizations are an imbedded part of the community. However, in the context of the community project, the same expectation should be applied to them as to the new community groups created for the project: demonstrating a clear commitment to the objectives, wellbeing of community members, and participation in the development and implementation of activities, having their plan approved by the community and holding regular progress updates with the community including transparent reporting of resources used and expenditures. Detailed action plans that do not compete but complement each other (especially timing). This is particularly the case in harsh settings such as camps, or postconflict areas. Whether interventions can work toward promoting sustainability, at least initially, will depend on the volatility of the context. Be honest with your beneficiaries on the intended objective of the livelihood opportunity. Avoid adding more stress People living in emergency situations already experience stress from a variety of sources. With this in mind, a Do No Harm approach should always be maintained, as there are significant risks of raising expectations (and disappointing) or leading to new or increased stresses. Any livelihood intervention needs to be chosen and designed carefully with this in mind, or else it risks adding rather than alleviating stress (Lund et al, 2011). As one example, micro-credit programs have been promoted for their potential to increase savings and stimulate economies. However, for people in volatile and uncertain situations, microcredit can add stress because of the pressure to plan for the future, and ultimately pay back loans (Kumar and Willman 2017). Direct cash transfers have gained ground in recent years as a means of stimulating local economies and promoting autonomy and are increasingly seen as a favorable alternative to conventional delivery of food and other relief items (Doocy and Tappis; 2016; Oxfam, 2010), and they are likely to create less stress than microcredit. Focus on building assets Livelihood interventions that build assets have demonstrated a positive impact on mental health and psychosocial well-being (Lund et al 2011). In emergency settings, this may mean focusing on assets that are transferable to other environments, such as trade or employment skills, or portable assets like small livestock or solar phone chargers. An impact evaluation found increased trust, decrease in tensions, and perceptions of greater mobility (Mercy Corps, 2018). Consider sensitivities of targeting Given the high perception of value from livelihoods interventions, particularly those which involve cash or asset transfers, targeting must be sensitively dealt with. Consult with stakeholders to understand dynamics of resentment, ensure that targeting does not privilege certain groups, and that decisions are communicated clearly. The initial market assessment should feed into the broader monitoring and evaluation system so that feedback can be incorporated, and adjustments made throughout the intervention. Whom it is critical to get perspectives of people from different backgrounds, genders, ages, ethnicity, religion and identified vulnerabilities in the assessment. Be sure to involve the communities, including the host community if appropriate, in the design. Identify potential risks and negative impacts and try and put mitigating mechanisms in place. Market analysis these typically focus on one or a few market systems for particular products or services. The information is drawn from interviews with different market actors, which can include private enterprises (especially small and medium businesses), government agencies and service providers. The aim of this analysis is to identify: laws and regulations for key markets; legal ability for displaced people to work; products and supply chains; infrastructure for production, transport, and distribution and any bottlenecks.
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So we described to them what we wanted to do and we asked these 17 people to tell their communities about this centre and its activities birth control kidney pain buy yasmin 3.03mg with mastercard. It belonged to the old regime birth control for women xxxl purchase 3.03 mg yasmin free shipping, then it was donated to the local community birth control for women in late 40s order yasmin 3.03 mg overnight delivery, and then there was an agreement between the local community and the Ministry of Social Affairs birth control pills for menopause symptoms yasmin 3.03mg lowest price. So it was a big fight to find a small place, which is actually outside Misrata, kind of 13 km away from downtown. The obj crease humani yan pop als to d ing the ans, an specific within th Tripoli, B Psycho A secon handle 15 283 mage. However, although the assessment provided invaluable insights, and two workshops were conducted in Tripoli and Benghazi to modify the tools with the teams, some of the interviewed staff regretted that the tools and methodology used for the assessment did not fully reflect Libyan needs and context. This is the first time we have had to manage so many people and these kinds of contracts. You need to have a radio all the time with you, so the administrative part is extremely heavy. Ideally it was hoped to have both international and national staff who could deal with the very fluid and demanding situations in the three proposed locations for the centres. However in reality it was difficult to recruit sufficiently qualified staff in a short time span. According to some respondents, a key challenge was represented by the fact that local staff recruited to work in the centres were not professionals with sufficient expertise in their specific areas of work. This would have been the only way possible for this kind of project to work as planned from its very beginning. The availability of local expert staff is quite low overall (and this is also recognized by other organisations and the local government. An added complexity compounding the difficulty in recruiting suitably qualified local staff were the low salary levels in the budget proposal, which by Libyan standards would not attract professionals with a good track record and where volunteerism and work for social causes is still a new phenomenon seen by many with a degree of distrust. Object betwee Multakama Centre, Tripoli, 2014 Several respondents also mentioned how social cultural norms vary from city to city, and from region to region. To cr for the the obj aims an involving benefic 17 285 work- e cenasis is menters o a cerand log suitasal, d track w phe- armed groups because they have heard music coming from the centre. It was important in a country where women do not usually work and are not able to travel alone, for example, that when women were recruited to the staff teams, there was careful planning in gender relations in terms of programmes and activities. To map community resources around the centres Mapping includes expressive/creative/ social resources in each locality. Three missions took place between March-May, May-July and September-December 2013. The Turin team initially experienced more difficulties than originally expected, especially due to security issues and restrictions on movement. The theatre event was restricted in its scope and the consultants found they were not able to use some of the techniques to connect with people directly in the streets. For instance, they often organize a community event by inviting people to donate fruit so as to make a big fruit salad together. However the caretakers open up the centre at 6 am, so as to allow people go jogging, especially women. So we open the centre at 6 am to give people an opportunity to do this kind of activity. However, although this idea was discussed and agreed upon initially, because of security reasons it could not be implemented. I talk to the student who then talks to his/her parents and so on, because the objective of the event in July was also that of reaching and involving the people living in the neighborhood, i. Some were traced through the Internet (for instance a martial art school); others were found by going to schools and a centre for disabled people. Students and residents of the centre were asked if they knew other people or resources that could be involved. A painter was identified who was willing to collaborate voluntarily and ran a workshop for children with the Turin consultants and accompanied by the centre staff so that they could learn in action. It was challenging to work in communities where there was so much distrust, especially regarding outsiders, resulting from 42 years of living under the Qadaffi regime. A lot of time is needed to build up trust and work directly with people in the community in these circumstances. In the words of one of the respondents: " the Turin collaborators spending their time in the centres from 8 am to 5 pm every day, accompanying the staff, mentoring them in their daily work, has really made a difference. Being there every day and assist them to structure their work, explaining them how this structured work should be carried forward, really made the difference". Not so much in terms of therapeutic elements, but rather more on the acknowledgment and realisation that there is a way of working that is greatly supportive in terms of relationship-building. Now, by working with the staff of the centre, the disabled club is now employing different approaches that emphasise expressivity. This fresco is a living testimony to the children that can also be used to talk about children and disability more generally. In the words of one of the staff: "Although we use the term in official papers, we do not use it within the centre. The centre in Misrata is called `Abdaa Mana for Social and Recreational Activities. It was also a challenge to deliver the message that the activities offered by the centre were not simply single activities, but were guided by a principle of supporting psychosocial wellbeing. This had to do with a lack of cultural vocabulary to discuss psychological or psychosocial problems. This would be overcome by teaching skills around communicating about emotions, but as one of the respondents from Misrata put it: "The main idea of the centre is to provide psychosocial support. On a whole, the accepted identity of the centres is therefore more of a recreational and leisure centre, providing a context for community people to gather. For example, there are few spaces for activities needing more privacy for participants and staff alike. For the future it will be important to consider ways of improving the physical structure of each centre so as to facilitate the management and implementation of the range of activities planned. Although the relationship between the centres is generally good, some respondents reported that there was not a sustained exchange of experience and ideas. This seems to be due not only to restrictions in movements between Misrata and Tripoli but according to some of the respondents, it is also the result of cultural and historical factors (including the role of the two cities in the toppling of the former regime. Sometimes they enquire how the others are doing, but sharing experience is not structured. It is significant in having had an impact directly on the population affected by the revolution and the current state of turmoil. Respondents who are directly involved in working in the centre and in the communities all mentioned that the concept of psychosocial work was hard for them to conceptualise. They found it hard to explain when they met people in the communities, but youth, children, mothers all come to the centre because it is a safe place where they feel protected. When asked about how the centres compare with existing services in Libya, respondents highlighted that the centres are functioning in a more effective way. But these centres are much less effective and have been seeking the assistance of the Misrata centre in providing quality activities. So the impact is good, not to Libyan standards, but compared to Misrata standards, I would say very good. But if you compare with (national) standards, the centre is still struggling to find a way to come up with a kind of approach which is consistent and adaptable to the community and the culture. These staff members are themselves drawn from the affected population, and live in the same difficult security situation as the rest of the population. For instance, it has proved to be a vital resource for the staff themselves to see that once trust has been built, skills in talking about emotions can be taught and supported, despite considerable cultural barriers. There was some initial resistance by the community to these women participating in the activities at the centre, but an agreement was made through an invitation from the centre being sent in response to a request for help from the women themselves. The idea is that everybody should understand that each person can change society and he/she should not wait for the government or whatever to change things. Then they started doing small initiatives in the school with a small number of kids, simple things that do not require lots of money and are suggested by the kids themselves, like taking care of the yard, building simple things. Then, they involved larger numbers of people, even involving local authorities, for instance, collecting tyres from the roads.
If we assume birth control for 5 years in the arm order 3.03mg yasmin fast delivery, as a working hypothesis birth control for women 60 yasmin 3.03mg online, that eight quanta are actually utilized in photosynthesis (while lost quanta absorbed above this number are eight primary photochemical the processes can be utilized for the transfer of four hydrogen atoms birth control and depression cheap 3.03mg yasmin free shipping. One is to activate the same four hydrogen atoms photochemically tvnce in succession birth control pills and breast cancer purchase 3.03mg yasmin otc. This kind of secondary reactions can be designated as "energy dismutations," because of their analogy to chemical dismutations repeatedly mentioned in this chapter. We will - taken away from water (or from an intermediate donor), as photoxidations, and those of the second set- in which the same hydrogen atoms are transferred to carbon dioxide (or an intermediate acceptor), as photoreductions (using this term in a sense different from that assigned to it by Gaffron, cf. The hypothesis two primary processes has often been associated with the assumption that the intermediate hydrogen acceptor is chlorophyll, and that this pigment is capable of taking hydrogen atoms away from water (or another donor), with the help of light, and transferring them to carbon dioxide (or another acceptor), also with the help of light. As announced before, we will postpone the question of the role of chlorophyll in photosynthesis until chapter 19, and use in the following or Z where the original papers may have used schemes the symbols Chi (= chlorophyll). However, we will retain the assumption that the X same catalyst whose oxidized form participates in the photoxidation of water also participates, in the reduced form, in the photoreduction of carbon dioxide. Photosynthesis, with oxidation-reduction reactions between three (The central intermediary catalysts as the two primary photochemical processes. In this scheme, the "photothat is, it was assumed to complex in the "photoreact directly with the carbon dioxide-acceptor reduction," and to be restored by an intermediate hydrogen donor in the "photoxidation. This special mechanism of catalytic water oxidation will be compared with the mechanism (7. A similar scheme can be devised also by assuming an "energy dismutation" on the "oxidation side" of the primary photochemical process, that is, by postulating that the recombination of four pairs of primary products gives four other primary oxidation products the power to oxidize water according to reaction (7. The descent one weight in a clock lifts the other weight to twice its original height, doubling its potential energy. When two excited mercury atoms collide, the result is often the excitation of one of them to twice its original energy level, and the return of the other into the ground state (c/. This analogy with chemosynthesis is the main reason for the introduction of the concept of "energy dismutation" into the discussion of the mechanism this concept enables one to postulate only one kind of photosynthesis. A possible mechanism of "energy dismutation" in photosynthesis and chemosynthesis will be discussed in chapter 9, and the results presented in schemes 9. Comparison of Different Primary Processes of photosynthesis presented Comparing in this chapter, critically the various schemes we can discard the four quantum schemes as contradicting recent quantum yield determinations, as well as straining dangerously the thermochemical possibilities. As between the alternative eight quanta theories, no final decision is possible at present. Two questions remain to be decided: Is the assumption of eight identical photochemical processes (as in 7. Does carbon dioxide or water (or both or neither) participate (directly or as complexes) in the primary photochemical process Although the hypothesis of two sets of primary photochemical processes photoxidations and photoreductions does not require the direct chemical participation of chlorophyll in both of them, an experimental proof of the existence of two interconvertible colored forms of chlorophyll belonging to different reduction levels and capable of using light energy for photoxidations and photoreductions, respectively, would - - see, in strengthen this hypothesis almost to the point of certainty. As to the second question, that of the direct participation of the reaction components in the primary photochemical process, the nonphotochemical reduction of carbon dioxide in autotrophic bacteria and hydrogen-adapted algae constitutes a strong, even if indirect, argument against the association of carbon dioxide with the photochemical reaction proper. One is tempted to attribute photosynthesis and chemosynthesis to a reaction of carbon dioxide with the same reducing agents, formed in one case by reductant. One such observation is the light-induced liberation of carbon dioxide, which occurs occasionally (c/. A second argument in support of a photochemical interaction between that chlorophyll and carbon dioxide thesis is the relationship between the photosyn- and chlorophyll fluorescence in vivo. However, in this case, too, an indirect interaction may suffice to produce the observed results. V, which contains two sets of different primary processes but leaves open the possibility of the same intermediate reductants occurring in photosynthesis and chemosynthesis, is our second choice, and would become the first one if the existence of two interconvertible green modifications of chlorophyll one a photo-oxidant and one a photoreductant would be definitely confirmed by experiments in vitro. The Primary Process in Bacteria and Adapted Algae In hydrogen-adapted algae and in bacteria, molecular hydrogen, hydrogen sulfide, or other inorganic or organic hydrogen donors replace water in the role of the ultimate reductant in photosynthesis. Does this substitution mean a change in the primary photochemical process, or merely a different course of secondary catalytic reactions Nakamura (1938), van Niel (1941), Franck and Gaffron (1941), and Gaffron (1942) all suggested, for different reasons, that the substitute reductants do not participate in the primary photochemical process. Since van Niel and Gaffron considered the oxidation of water as one even the only) primary photochemical reaction in ordinary photosynScheme 7. The fact that purple bacteria do not evolve oxygen in light could then be explained in two ways. The identity of the primary processes in adapted and ordinary green algae is supported by the observations of Rieke and Gaffron (1943) that the maximum quantum yield and the saturation rate in flashing light are the same in the photoreduction by adapted algae as in the photosynthesis in the nonadapted In the case of purple bacteria, on the other hand, the primary state. In adapted algae, this recovery is blocked, and a reaction with a substitute reductant. Howsink, Katz, ever, this hypothesis disagrees with the assumption, made in chapter 6, that the hydrogenase system, even if it acquires hydrogen from different donors by means of specific "oxidoreductases," transfers it to a common acceptor (designated by Ah in Chapter 6). This seems to leave no place for a specific photocatalyst between Ah and carbon dioxide. Bibliography to Chapter 7 the Primary Photochemical Process 1914 1916 1918 1923 Bredig, G. Since these reactions proceed at low temperatures, they probably require Some of these undoubtedly are true enzymes, while others be comparatively simple organic, or even inorganic, compounds. The realization that photosynthesis includes nonphotochemical reAbout 1905, Blackman had action steps first came from kinetic studies. Willstatter and Stoll suggested, more specifically, that the Blackman reaction may be the liberation of oxygen from peroxides. Warburg thought at first that the Blackman reaction consists in a transformation of carbon dioxide preliminary to its participation in the photochemical reaction, but later agreed with the Willstatter-Stoll hypothesis because of the similarity which he found between the effects of poisons on photosynthesis and on catalase activity (c/. Suggestions that there may be several "Blackman reactions" were made repeatedly, but without much conviction, until Franck postulated, on the basis of an analysis of different catalytic reactions. He made no suggestion as to the chemical nature of this reaction, but our discussions in chapter 7, would indicate that it may possibly be a dismutation, 172. These three catalysts are only a minimum; and the actual number of nonphotochemical reactions in photosynthesis may be larger than three. The evolution of oxygen, for example, may require two successive catalytic reactions (c/. The equiUbrium may be by cations whose carbonates have a small solubility product, for example, Ca++ or Mg++. Thiel and Strohecker (1914) and Strohecker (1916) measured a comparatively slow its rate in the alkaline region. More recently, Brinkman, Margaria and Roughton (1933) determined of hydrogen-ion concentrations. Hydration and dehydration are accelerated by the anions of many weak this is phosphate, borate, and acetate (Roughton and Booth 1938). Further results on the rate of hydration of carbon dioxide were obtained by Mills and Urey (1939, 1940) by the use of isotopic indicators. The apparent first dissociation constant of carbonic acid (1933), was redetermined by Maclnnes and Belcher who found: Kauko and Carlberg dissociation constant is (1935) obtained a smaller value, 3. It was studied by Siegfried and Howwjanz (1909), who 1 observed the absorption of 0. In aqueous alcohol, carbon dioxide becomes an object by Faurholt propanol and between water and alcohol. The resulting equilibria have been studied and Faurholt and Jespersen (1933), for methanol, ethanol, sucrose. They found that the contribution of alcohols to the absorption of carbon dioxide in alcohol-water mixtures is comparatively small and disappears on both side of the "bicarbonate range" (pH around 8. In addition to the rapid gas uptake by dissolution, they noticed a slow absorption which they attributed to esterification. Since phytol is a component of chlorophyll, Baur considered this result as significant for the carbon dioxide fixation in photosynthesis. This restricts the contribution of amines to the carbon dioxide absorption by aqueous solutions. Siegfried (190512), Siegfried and Neumaim (1908) and Siegfried and Liebermann (1908) have studied quaUtatively the formation of carbamates in aqueous solutions of amines, amino acids, peptones, and proteins, in the presence of alkali (calcium hydroxyde) and Fichter and Becker (1911) have observed the formation of carbamate from gaseous methyl amine and carbon dioxide at low temperatures. Siegfried suggested that the fixation of carbon dioxide by amino acids may be He claimed (1905^) that this reaction can occur even of importance for photosynthesis.
However birth control that stops periods buy discount yasmin 3.03 mg line, the work of Spoehr and Smith on sunflower leaves has opened the way to a observations of the absorption of carbon dioxide is a prerequisite for the complete understanding of the fate of carbon dioxide in photosynthesis birth control pills 2 hormone provera order yasmin 3.03 mg overnight delivery. From the studies of Smith birth control reminder order yasmin 3.03mg online, water birth control pills side effects buy 3.03 mg yasmin with mastercard, phosphate, and alkaline earth carbonates emerge as the three main factors determining the carbon dioxide balance of nonilluminated leaves under high partial pressures of carbon dioxide. It was mentioned above that the carbon dioxide balance of blood was originally attributed exclusively to the conversion of carbonates more quantitative treatment, which into bicarbonates. A similar development may possibly occur in the theory of the carbon dioxide absorption by plants; but the suggestion of Willstatter and Stoll that carbamination is the inain factor in this absorption is not borne out by the analysis of Spoehr and Smith. This component is small at the low carbon dioxide concentrations, but grows with increasing pressure, when the chemical absorbers become saturated. Since an average leaf is about 80% water, the first concentration corresponds to about 2 X 10-'%, and the second to 0. A correction is needed nonelectrolytes in exact calculations for the effect of salts and carbon dioxide. He noticed also that expressed and acidified cell sap absorbs about 10% less carbon dioxide than the same volume of pure Leaves of Sedum prealtum, whose sap has a strongly acid reaction water. Conversion of Carbon Dioxide into Bicarbonate in Plants cell dioxide would be water were unbuffered, about 15% of dissolved carbon in the form of bicarbonate ions in ordinary air, and a proportion in an atmosphere enriched in carbon dioxide. If the the presence and Andre in in plants of solid carbonates was discovered by Berthelot dioxide (that is. However, the properties of sunflower are not exceptional, as shown by the later data of Smith (1940), some examples of which are given in table 8. This conclusion is borne out by the observations that yellow leaves absorb the same quantities of carbon dioxide as green leaves (Willstatter and Stoll), that white leaves also yield carbon dioxide in vacuo (Schafer), and that stalks, roots, and petals show^ the same reversible carbon dioxide absorption as leaves (Smith). Schafer found that the quantity of dissociable carbon dioxide increases in light; but this can scarcely be taken as an indication of a direct relationship between the agent absorbing carbon dioxide and the photochemical apparatus of the leaves. Fraction 3 behaves as a buffered solution which takes up carbon dioxide under pressure (in excess of the solubiUty of this gas in pure water) bonate, but releases this all of it upon evacuation. This interpretation is confirmed by the properties of fractions 5 and 6, since they show that the carbon dioxide-absorbing component of fraction 4 is completely soluble in carbonated water. This can only be explained by assuming the presence of carbonates in such a state or location that they are unable to take part in the absorption of gaseous carbon dioxide, but can be decomposed by acid. This is a little more than the observed effect; but not all alkahne earths need to be present as carbonates. Because of the permeability of cell membranes to carbon dioxide molecules, changes in the external concentration of this molecular species produce shifts in the carbonate concentration inside the cell (accompanied by changes in the acidity of the aqueous cell phases). Whether variations in the external concentration of bicarbonate ions, for which the cell membrane is almost impermeable, also affect the composition of the carbonic acid system in the cell, is a complicated problem of membrane equilibrium, and as long as we do not know the answer, experiments with varying concentrations of carbonate ions in the external medium do not play inside the tell us anything definite about the part which these ions cell. If the presence of carbonate anions in the medium does have an influence on the composition of the carbonic acid system within the cell (in the equilibrium state or in the steady state of illumination), this influence is at least several orders of magnitude smaller than that of free carbon dioxide molecules. At first sight, certain results of Arens (1930, 1933, 19361-2) seem to contradict the conclusions of Osterhout and Dorcas. The interesting aspect of the phenomenon is that the deposition of calcium carbonate often takes place on the upper surface only. According to the latter, the flow of carbonic acid into the cells is maintained practically exclusively even when the medium contains a this makes it probable that the ions, cannot penetrate through the membranes at all. Simultaneously with this comparatively slow flow of carbonates and bicarbonates across the cell, a much larger quantity of free carbon dioxide unobserved in Arens technique enters the cell (as shown by Osterhout and Dorcas), to be completely consumed there the opposite side of the cell in - by photosynthesis. It must be added that the correctness of the results of Arens is not beyond doubt. Gessner (1937) found, for instance, by experiments with vaseline-covered leaves, that both surfaces of Elodea leaves are equally active photosynthesis. To sum up all experiments described so far do not teach us anything about the true role of carbonate ions in photosynthesis. While we find no basis for the claim that carbonate ions play a direct part in photosynthesis, neither can we assert that they play no such part at all. If, however, only the neutral complex can take part in photosynthesis, then the presence of anions, although it cannot affect the equihbrium concentration of the reduction substrate, may accelerate the: -, - rate of its formation. One argument has been presented in favor of the assumption that the main reaction sequence of photosynthesis does not include the intermediate formation of bicarbonate ions. It was based on an estimate of the rate of hydration of carbon dioxide in the cell, a rate which appears to be too slow to allow all the reduced carbon dioxide molecules to pass through the hydration stage. It was mentioned on page 175 that the (noncatalyzed) hydration of carbon dioxide requires about one minute at room temperature. Consequently, only about 5 X 10~^ X p moles of carbon dioxide (p = carbon dioxide pressure in mm. He concluded that hydration of carbon dioxide cannot represent a necessary:: step in photosynthesis. Experiments carried out catalysts It may cells is by Burr (1936) failed to reveal any catalj^tic effects of mashed leaves on the hydration velocity of carbon dioxide; and the same result was obtained by Mommaerts (1940). Neish (1939), on the other hand, gave some figures for the carbonic anhydrase activity of leaf matter as a According whole, and of separated chloroplast matter (Table 14. The carbon dioxide-bicarbonate-carbonate equihbrium even if it in the cells, does not lie in the direct path of photosynthesis, may play a part in this process by providing carbon dioxide reserves within the cell which help to even out short-time variations in the external supply of 200 this substrate. Figure 20 shows the rapid decline in the rate of oxygen evolution by Hydrilla and Cabomha which follows a transfer of their twigs into distilled water. We shall now describe experiments which indicate that a different (although also a reversible and nonphotochemical) absorption of carbon dioxide is closely associated with photosynthesis presumably the as a preliminary step in this process (as assumed in Chapter 7). On the dioxide content - other hand, the affinity of the acceptor responsible for this absorption to carbon dioxide of the phosphate or carbonate carbon dioxide pressures of the order of 1 mm. This value is derived from the "carbon dioxide" curves of photosynthesis (representing rate vs. The carboxylation equilibrium is assumed by Franck to lie very far on the association side, even at the lowest carbon dioxide pressures. This hypothesis implies that the free energy of carboxylation is even more negative than the above calculated value of -6 kcal per mole. Ruben (1943) suggested that the strong affinity of the unknown be caused by a coupling between its carboxylation and the hydrolysis of an "energy-rich" organic phosphate which occurs with the liberation of 10 to 12 kcal per mole (c/. If the uptake of one molecule of carbon dioxide were coupled with the formation of one molecule of inorganic phosphate from an acceptor for carbon dioxide may "energy-rich" phosphorylated molecule, the net change in free energy could be of the magnitude required for the explanation of the early carbon dioxide saturation of photosynthesis. In chapter 5, the experiments of Vogler and Umbreit (1942) on After a period of sulfur of inorganic Thiohacillus thiooxidans have been described. It was suggested on page 114 that this absorption probably is a preliminary fixation. In the second place, the amount of liberated phosphate is only one-fiftieth of that of absorbed carbon dioxide. The fixation of C*02 in the dark was first observed by Ruben, Hassid, and Kamen (1939) in barley leaves and by Ruben, Kamen, Hassid, and Devault (1939) in the properties of the compound formed by this "dark Chlorella. The part of the absorbed radioactive carbon dioxide which was not removed by this 1. We referred to the saturation in figure 21 as "apparent" because of 10% the observation that the maximum uptake can be further increased by alternative evacuation of the cell suspension and its exposure to radioThe maximum absorption obtained in this way active carbon dioxide. Furthermore, cells with different chlorophyll concentrations pacity, show no differences in C*02-absorbing ca- and etiolated plants also are able to absorb carbon dioxide. Frenkel (1941) exposed Nitella plants to C*02 for 25 minutes, and Tkf disintegrated the cells in 0. When intact cells were first exposed to C*02 in the dark and then crushed and exposed to light, no transfer of activity from the aqueous phase into the chloroplasts could be observed. The and 30-50% of the active barium salt is transformed the theoretical value for complete into carbonate by dry distillation. Attempts to identify the complex by coprecipitation with one of the famihar plant acids (ascorbic, citric, fumaric, maleic, succinic, oxaUc, or this appears understandable in the tartaric) gave no positive results. Vsec; from this they active complex, and found estimated the molecular weight as being close to 1500. Smith and Cowie (1941) also observed the absorption of radioactive carbon dioxide by plants in the dark. Their results discussed on pages 192 to 195 have been confirmed; and, as a new result.
Proven yasmin 3.03 mg. How Effective Is The Patch?.
