Translocation as a strategy to rehabilitate the queen conch (Strombus gigas) population in the Florida Keys

Queen conch (Strombus gigas) stocks in the Florida Keys once supported commercial and recreational fisheries, but overharvesting has decimated this once abundant snail. Despite a ban on harvesting this species since 1985, the local conch population has not recovered. In addition, previous work has reported that conch located in nearshore Keys waters are incapable of spawning because of poor gonadal condition, although reproduction does occur offshore. Queen conch in other areas undergo ontogenetic migrations from shallow, nearshore sites to offshore habitats, but conch in the Florida Keys are prevented from doing so by Hawk Channel. The present study was initiated to determine the potential of translocating nonspawning nearshore conch to offshore sites in order to augment the spawning stock. We translocated adult conch from two nearshore sites to two offshore sites. Histological examinations at the initiation of this study confirmed that nearshore conch were incapable of reproduction, whereas offshore conch had normal gonads and thus were able to reproduce. The gonads of nearshore females were in worse condition than those of nearshore males. However, the gonadal condition of the translocated nearshore conch improved, and these animals began spawning after three months offshore. This finding suggests that some component of the nearshore environment (e.g., pollutants, temperature extremes, poor food or habitat quality) disrupts reproduction in conch, but that removal of nearshore animals to suitable offshore habitat can restore reproductive viability. These results indicate that translocations are preferable to releasing hatchery-reared juveniles because they are more cost-effective, result in a more rapid increase in reproductive output, and maintain the genetic integrity of the wild stock. Therefore, translocating nearshore conch to offshore spawning aggregations may be the key to expediting the recovery of queen conch stocks in the Florida Keys.

Expedición naútica científica Fray Francisco Morillo, río Bermejo, Argentina, 29/09-10/10/1984

El próximo septiembre se cumplen treinta años de la llamada Expedición Naútica-Cientifíca “R. P. Francisco Morillo” realizada en botes neumáticos por un grupo de personas de diferentes orígenes y entre los que se encontraban naturalistas y profesionales de las Ciencias Naturales. A nivel profesional fue una gran experiencia, ya que me permitió transitar por un ámbito geográfico de difícil acceso, con flora y fauna cuya referencia la tenía solo a través de textos. Por otra parte y mirado a la distancia, fue muy interesante el comportamiento humano del grupo. Entiendo que un sociólogo podría dar alguna interpretación, pero he visto de todo, actos de solidaridad, de mezquindad, egoísmo y de cierta locura, como por ejemplo, querer matar un yacaré por el simple hecho de que estaba en la playa tomando sol. En este caso, la suerte estuvo del lado de la noble bestia, ya que los involucrados en las Ciencias Naturales pudimos detener semejante barbaridad y hacer comprender a los de “gatillo fácil” que no había ningún sentido en lo que querían hacer. Irónicamente, entre otras cosas, este viaje tenía dentro de sus objetivos participar en un Congreso de Conservación… Los objetivos del viaje para los naturalistas, sólo se cumplieron en parte, ya que al principio de esta travesía comenzaron a suscitarse problemas, principalmente por las características del río, lo que dificultó, por falta de tiempo, la toma de muestras y las consiguientes observaciones. A nivel personal me queda la riqueza que me dio esta experiencia y el haber conocido a dos personas que me llamaron profundamente la atención. A nuestro baqueano José “Pipo” Marty, un hombre generoso y de una gran sabiduría. El otro fue Exequiel Martínez, al que conocí en el congreso que se realizaba en Resistencia y con quién, a partir de ese momento, me une un lazo afectivo que nace de un profundo respeto y admiración.

Modelling of equipment loaded panels for robust control investigations

This paper develops a modelling technique for equipment load panels which directly produces (adequate) models of the underlying dynamics on which to base robust controller design/evaluations. This technique is based on the use of the Lagrange's equations of motion and the resulting models are verified against those produced by a finite Element Method Model.

Initial modelling and controller design for active control of spacecraft microvibrations

Microvibrations, at frequencies between 1 and 1000 Hz, generated by on board equipment, propagate throughout a spacecraft structure affecting the performance of sensitive payloads. The purpose of this work is to investigate strategies to model and reduce these dynamic disturbances by active control. Initial studies were performed by considering a mass loaded panel where the disturbance excitation source consisted of point forces, the objective being to minimise the displacement at an arbitrary output location. Piezoelectric patches acting as sensors and actuators were used. The equations of motion are derived by using Lagrange's equation with modal shapes as Ritz functions. The number of sensors/actuators and their location is variable. The set of equations obtained is then transformed into state variables and some initial controller design studies have been undertaken. These are based on feedback control implemented using a full state feedback and an observer which reconstructs the state vector from the available sensor signal. Here, the basics behind the structural modelling and controller design will be described. This preliminary analysis will also be used to identify short to medium term further work.

含联萘基团旋光性聚合物的设计、合成与手性光学性质

随着材料科学的飞速发展，人们对具有不同结构和性能的聚合物材料提出了更高、更广泛的要求，合成出具有新型结构的聚合物，并研究其独特的性质和功能已成为当今高分子领域研究的主要方向。旋光性聚合物具有独特的不对称结构，在自然界的生物体中，旋光性大分子特有的不对称结构在维持生命过程、新陈代谢、物种繁衍、进化等方面都起着决定性的作用，在人工合成聚合物领域，旋光性聚合物也已经在手性识别和对映体拆分方面取得了广泛应用，并在手性催化剂、液晶、光开关、非线性光学和生物医药等领域表现出了潜在的应用前景。在本论文中，我们以具有强轴手性结构的2,2'-取代1,1'-联萘为手性源，设计并合成得到了多个系列的旋光性和非旋光性聚合物，取得了一些有意义的结果。1．含联萘基团旋光性聚酰亚胺的合成与性质从1,1'-联-2-萘酚出发合成了新型旋光性和非旋光性二酐单体，即2,2'-(3,3',-(3,3', 4,4'-四酸二酐)二苯甲酰氧基-1,1'-联萘((±)-，(R)-和(S)-BNDEDA)，并通过BNDEDA和2,2'-(3,3', 4,4'-四酸二酐)二苯甲酰胺基-1,1'-联萘((±)-和(S)-BNDADA)同各种二胺的缩合聚合，制备得到了一系列旋光性和非旋光性聚酯酰亚胺PEIs和聚酰胺酰亚胺PAIs。(1) 所得芳香聚酰亚胺都具有良好的溶解性，较高的玻璃化转变温度和热分解温度：(2) PAIs和PEIs同它们相应的模型化合物在DMF溶液中具有基本相同的紫外可见吸收光谱，这说明聚合物沿分子主链方向的共轭长度局限在重复单元的结构之内，因此PAIs和PEIs溶液涂敷所得薄膜均表现出良好的透光性；(3) PAIs和PEIs都是非晶聚合物，但是它们在2θ为～12°处出现的衍射峰又说明在聚合物体系中存在着一定的长程有序结构，PEIs的有序性要高于PAIs的有序性，偶数亚甲基长脂肪链的引入没有造成PEI有序性的明显提高，而奇数亚甲基长脂肪链的引入则使得PEI在2θ为12°处的衍射峰更为明显；(4) 由于无法紧密排列，高分子链间的相互作用力不强，因此旋光性和非旋光性聚合物在热性能、溶解性和结晶性等方面均没有表现出明显差异；(5) 旋光性芳香PAls和PEIs都具有比它们相应模型化合物高的特性旋光值，CD谱图和构象分析结果表明，由于1,1'-联萘基团的轴手性和分子主链的刚性，旋光性芳香PAIs和PEIs的高分子链都具有高级手性构象结构；(6) 由于1,1'-联萘基团的二面角随着温度的升高而发生变化，因此聚合物的手性光学性质对温度表现出了明显的依赖关系。(7) 旋光性PAIs在DMF溶液中和在固体状态下都具有很好的旋光热稳定性，旋光性PEIs在固体状态下于玻璃化转变温度加热48 h也没有出现旋光能力的降低；(8) 光学双折射测试结果表明，溶液涂敷所得非旋光性聚合物薄膜的负性双折射要强于相应旋光性聚合物薄膜的负性双折射。2．新型联萘二酐和二胺单体的合成与聚合从1,1'-联-2-萘酚出发对1,1'-联萘基团的不同取得位置进行官能化，合成得到了九种14个新型联萘化合物，并成功地将改进的Curtius和Gabriel反应应用到联萘类二胺单体的合成中。利用所合成的新型二酐单体和二胺单体分别同各种二胺和二酐的缩合聚合，制备得到了一系列具有新型结构的非旋光性芳香聚酰亚胺，聚合物表现出良好的溶解性，较高的玻璃化转变温度和热分解温度。X-射线衍射谱图说明高分子链从1,1'-联萘基团6,6'-位连接所得聚酰亚胺具有较好的结构有序性。3．主链螺旋聚甲基丙烯酸联萘酚单甲醚酯的合成与表征从2-甲氧基-2'-羟基-1,1'-联萘出发，合成得到了新型旋光性和非旋光性甲基丙烯酸酯聚合单体，并在AIBN的自由基引发作用下聚合得到了具有主链螺旋结构的新型旋光性聚合物。(1) 手性光学性质的研究结果表明，旋光性聚甲基丙烯酸酯具有主链单手螺旋结构；(2) 聚合过程中不存在对映体选择性或对映有择性的聚合方式：(3) 聚合物核磁氢谱的研究结果表明，在旋光性聚合物体系中，位于侧链的联萘基团可能取两种构象结构，即动力学稳定和热力学稳定的构象。随着旋光性聚合物单手主链螺旋结构的形成，使甲氧基处于较高屏蔽状态下的联萘反式构象成为动力学稳定构象；(4) 变温核磁氢谱的研究表明，温度升高将造成动力学稳定的联萘反式构象结构在聚合物中的比例减少，并伴随着聚合物特性旋光值的降低，同时热力学稳定的联萘顺式构象结构在聚合物中的比例在增加；(5) 手性光学性质和核磁氢谱的研究结果表明，旋光性聚合物的主链手性构象（与侧链上联萘基团的构象相对应）对分子量的高低具有依赖关系；(6) 聚合单体同具有不同对映体过量的旋光性聚合物具有基本相同的紫外吸收光谱，说明旋光性聚合物中联萘基团构象结构的变化并未造成共轭程度的较大变化。而无论旋光性或是非旋光性聚合物所表现出来的荧光性则说明在聚合物体系中可能存在着联萘侧基的相互作用，形成了π电子跃迁。4．含联萘基团旋光性聚酯和聚酰胺的合成与性质通过(±)-和(S)-2,2'-二甲氧基-1,1-联萘-6,6'-二酰氯（(±)-和（S)-DMBNDC）分别同1,1'-联-2-萘酚进行的界面缩聚，以及分别同各种芳香二胺在DMAc中的溶液缩聚合成得到了一系列旋光性和非旋光性聚酯和聚酰胺。(1) 聚合过程中不存在对映有择或对映体选择性的聚合方式；(2) GPC、~1H NMR谱图以及激光质谱的研究结果表明，DMBNDC同1,1'-联-2-萘酚的缩合产物可能主要以环状低聚物的形式存在；(3) 根据DMBNDC同1,1'-联-2-萘酚缩合所得产物的特性旋光值可以推断在聚合物体系中DMBNDC和1,1'-联-2-萘酚的手性结构具有良好的加和性：(4) (±)-和(S)-DMBNDC同各种芳香二胺聚合所得非旋光性和旋光性聚酰胺都表现出良好的溶解性，较高的玻璃化转变温度以及热稳定性。旋光性聚酰胺具有比相应非旋光性聚酰胺高的玻璃化转变温度；(5) 广角X-射线衍射谱图上的弥散峰表明所得聚酰胺具有非晶结构，但是随着二胺单元结构刚性的增强，聚合物在～13°处出现了新的衍射峰，说明聚合物结构的有序性得到了增强：(6) 旋光性聚酰胺都具有比模型化合物(S)-7高的特性旋光值，而且不同二胺单元结构造成了聚合物特性旋光值的较大变化，构象分析结果表明在旋光性聚酰胺的分子主链上存在着高级手性构象。

Informes de avaliação de genótipos de girassol 2007/2008 e 2008.

Características Gerais da Rede de Ensaios de Avaliação de Genótipos de Girassol. Resultados dos Ensaios Finais de Primeiro e de Segundo Ano - safra 2007/2008 e safrinha 2008. Ensaio Final de Segundo Ano - safra 2007/2008: Encruzilhada do Sul (RS). Três de Maio (RS), Curitiba (PR), Leme do Prado (MG). Locais não considerados na análise conjunta. Análise conjunta. Ensaio Final de Primeiro Ano - safra 2007/2008: São Gabriel (RS), Santa Cruz do Sul (RS), Xaxim (SC), Jaguariúna (SP), Mocambinho (MG) Leme do Prado (MG), Roda Velha (BA), Ipanguaçú (RN). Locais não considerados na análise conjunta. Análise conjunta. Ensaio Final de Segundo Ano - safrinha 2008: Londrina (PR), Manduri (SP), Cravinhos (SP), Uberaba (MG), Muzambinho (MG), Rio Verde (GO), Planaltina (DF), Chapadão do Sul (MS), São José dos Quatro Marcos (MT), Campos de Julio (MT), Vilhena / Ensaio A (RO) Vilhena / Ensaio B (RO), Bom Jesus (PI). Locais não considerados na análise conjunta. Análise conjunta. Ensaio Final de Primeiro Ano - safrinha 2008: Londrina (PR), Jaboticabal (SP), Manduri (SP), Patos de Minas (MG), Planaltina (DF), Vilhena . Ensaio A (RO) Vilhena . Ensaio B (RO), Mata Roma (MA). Locais não considerados na análise conjunta. Análise conjunta. Lista dos genótipos de girassol avaliados e registrados no Ministério da Agricultura, Pecuária e Abastecimento - MAPA.

Efeito da fertirrigação nitrogenada no rendimento de grãos de genótipos de trigo, no cerrado.

2007