Characteristics of natal and non-natal kit fox dens in the northern Chihuahuan Desert

We studied kit fox den characteristics of the northern McGregor Range of Fort Bliss Military Reservation, New Mexico, during 1994 to 1995. Twenty radio-collared kit foxes used 132 different dens, including 16 natal dens. Kit fox dens were located primarily in creosote-dominated habitat found in relatively flat, well-drained terrain. Natal dens were virtually indistinguishable from non-natal dens; however, natal den entrances were taller than non-natal den entrances. Entrances found at all dens were oriented more frequently toward the northwest and southwest. Kit foxes used more dens during the breeding (January-February) and pup-rearing season (May-July) than during gestation.     

L'introuvable révolution scientifique. Francesco Redi et la génération spontanée

The Italian naturalist F. Redi established in 1668 that insects are not produced by the way of equivocal generation, contrary to what was affirmed since the Antiquity. For that reason, many historians of sciences acknowledge his experiments, like those of Galileo, Boyle or Huygens, contributed to the scientific revolution that emerges in the seventeenth century in Western Europe. Based on the commentaries sparked off by the works of Redi, in his time and today, our contribution shows on the contrary that nothing at all in his approach reveals such an intention. Questioning without arrogance the knowledge and the authority of the Ancients, careful interrogation of the literariness of the Scriptures, adoption of an experimental reasoning still dependent on the scholastic argumentation, those are the main characteristics of his work. But those also could be the ones of Harvey, Borelli or Swammerdam's works. To defend the idea of a scientific revolution in the life sciences similar in its conditions and tempo to the one described in the history of the physical sciences would be a mistake, not to say an anachronism.     

Atomic structure holography using thermal neutrons.

The idea of atomic-resolution holography has its roots in the X-ray work of Bragg and in Gabor's electron interference microscope. Gabor's lensless microscope was not realized in his time, but over the past twelve years there has been a steady increase in the number of reports on atomic-resolution holography. All of this work involves the use of electrons or hard X-rays to produce the hologram. Neutrons are often unique among scattering probes in their interaction with materials: for example, the relative visibility of hydrogen and its isotopes is a great advantage in the study of polymers and biologically relevant materials. Recent work proposed that atomic-resolution holography could be achieved with thermal neutrons. Here we use monochromatic thermal neutrons, adopting the inside-source concept of Sz?ke, to image planes of oxygen atoms located above and below a single hydrogen atom in the oxide mineral simpsonite.     

Leadership and Power in Fostering a Collaborative Community in a Non-Profit Professional Organization

This article provides an account of first-person action research used for organization development in an all-volunteer professional organization. During a 12-month period, members sought to build a collaborative community out of a formerly defunct group. As part of this project, the group’s leader conducted a self-study by examining his role in exercising power while leading the group in building a collaborative community. Although the goals to collaborate and explore power relations originate in different philosophical perspectives, they were combined with moderate success in this project. An ongoing theoretical analysis of the challenges in using this approach illustrates the complications of combining collaborative approaches with the exploration of power.     

Reproductive pair correlations and the clustering of organisms.

Clustering of organisms can be a consequence of social behaviour, or of the response of individuals to chemical and physical cues. Environmental variability can also cause clustering: for example, marine turbulence transports plankton and produces chlorophyll concentration patterns in the upper ocean. Even in a homogeneous environment, nonlinear interactions between species can result in spontaneous pattern formation. Here we show that a population of independent, random-walking organisms ('brownian bugs'), reproducing by binary division and dying at constant rates, spontaneously aggregates. Using an individual-based model, we show that clusters form out of spatially homogeneous initial conditions without environmental variability, predator-prey interactions, kinesis or taxis. The clustering mechanism is reproductively driven-birth must always be adjacent to a living organism. This clustering can overwhelm diffusion and create non-poissonian correlations between pairs (parent and offspring) or organisms, leading to the emergence of patterns.     

A new monotypic genus of chiggers and four new species of Quadraseta from Venezuela (Acari: Trombiculidae)

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Carebareia, n. gen., and its type - species, C. johnstoni, n. sp., are described. The genus Quadraseta Brennan, 1970, is redefined and a key to the 11 included species given. Four new species, Quadraseta tachirensis, holotype ex Akodon sp., Q. rotstieri, ex Proechimys guyannensis, Q. mirandae, holotype ex Oryzomys albigularis, and Q. falconensis, ex Sylvilagus floridanus, are described.     

Soil water and temperature response to prescribed burning

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Prescribed burning of Texas wintergrass ( Stipa leucotricha Trin. & Rupr.) communities reduced soil water contents for two to six months, and additional reductions occurred when the subsequent crop of cool-season grasses and forbs began growth. These soil water reductions occurred despite reduced plant production following burning. Soil water reductions were greater at 15 to 45 cm depths than in the upper 15 cm and greater following spring burning. Soil temperatures were higher on burned plots for most of the first year following burning.        

Mushroom consumption (mycophagy) by North American cervids

Native mushrooms play an important, though often underestimated, role in deer, elk, and caribou diets in North America. Mushrooms are often noted as an unusual or anomalous food in the diets of cervids; yet they often dominate diets in the late summer and fall in forested areas of western North America and throughout the year in the southeastern U.S. Mushrooms are particularly high in protein (16-19%), phosphorus (average 0.75%), and potassium (average 2%). Also, mushroom production is generally greatest in fall. Therefore, they are a highly nutritious food in late season when other native forages may marginally meet basal nutrient requirements of ungulates.