Masticatory proprioception in reptilians (Caiman sclerops)

Riassunto Mediante microelettrodi di tungsteno si é registrata l'attività unitaria del nucleo mesencefalico del trigemino inCaiman sclerops curarizzato. Le cellule di questo nucleo, silenti in condizioni di riposo, vengono attivate dall'abbassamento della niandibola e dallo stiramento del muscolo massetere omolaterale. Le risposte sono del tipo indotto da fusi neuromuscolari.     

Relationship of gasserian cells to extraocular muscle proprioception in lambs

Riassunto È stato isolato nel ganglio semilunare dell'agnello un limitato gruppo di cellule la cui scarica unitaria è tipicamente ed esclusivamente modificata dallo stiramento di singoli muscoli oculari. Tali risposte sono del tipo di quelle indotte dai fusi neuromuscolari. Si trae la conclusione che nel ganglio di Gasser dell'agnello si trovano i pirenofori di fibre che provvedono alla sensibilità propriocettiva dei muscoli estrinseci dell'occhio.     

Relationship of the mesencephalic trigeminal cells to jaw muscle proprioception in birds

Riassunto Nell'anitra curarizzata è stata registrata mediante microelettrodi di tungsteno la scarica unitaria di cellule trigeminali ubicate nella commessura posteriore. Questa viene modificata dai movimenti della mandibola e dallo stiramento di singoli muscoli che vi si inseriscono. Dette risposte sono del tipo di quelle indotte dai fusi neuromuscolari.     

Theory (In-)Equivalence and conventionalism in f(R) gravity

f(R) Gravity is the most natural extension of General Relativity within Riemannian Geometry. Due to (inter alia) its potential capacity for a unified treatment of early and late-time cosmic expansion, it has enjoyed recent attention in astrophysics and cosmology. I critically examine three inter-related claims found in the pertinent physics literature, of general interest to the philosopher of science. 1. f(R) Gravity is equivalent to a particular Brans-Dicke Theory. 2. The spacetime geometry underpinning f(R) Gravity has substantial conventional elements. 3. f(R) Gravity is an instance of a theory in which the distinction between matter and spacetime is conventional. Whilst the first claim can be vindicated in precise terms, the remaining two claims, I submit, are unwarranted – at least for the reasons usually adduced. On different grounds, though, the case for conventionalism about spacetime geometry in f(R) Gravity (as well as General Relativity) turns out to be considerably stronger.     

聚合质量比对Sr0．7La0．15Ce0．15Fe11.7Zn0．3O19／PAn复合体系微波吸收性能的影响

用原位聚合法制备了Sr0．7La0．15Ce0．15Fe11.7Zn0．3O19铁氧体／聚苯胺（PAn）复合材料。采用X射线衍射（XRD）、扫描电子显微镜（SEM）对样品的结构、微观表面形貌和粒子大小进行了表征,用微波矢量网络分析仪测量样品在2～12．4GHZ频率范围内复介电常数和复磁导率,根据测量数据计算微波反射率R与频率f的关系。研究结果表明：PAn包覆于掺杂锶铁氧体表面,PAn／Sr0．7La0．15Ce0．15Fe11.7Zn0．3O19复合材料具有良好的吸波性能,随着掺杂锶铁氧体含量的增加,微波吸收匹配厚度和吸收带宽发生变化：当Sr0．7La0．15Ce0．15Fe11.7Zn0．3O19聚合质量比为40％时,最佳匹配厚度为2．6mm,吸收峰值接近-40dB,峰值频率高于12．4GHz,大于10dB吸收带宽预计达到55GHz。     

Amperometric studies on chromium (III) and iron (III) hydroxocyanotungstates (IV)

Zusammenfassung Die Zusammensetzung von in wässeriger Lösung gebildeten Ionenpaaren des Anions [W(CN)₄(OH)₄]^4- mit Cr³⁺ bzw. Fe³⁺ wird amperometrisch ermittelt.

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Acknowledgment. The authors are grateful to Dr.S. M. F. Rahman for providing necessary facilities and C.S.I.R. (India) for awarding a Junior Fellowship to one of them (K. U.).     

Variation in chromosome number in the sheep headflyHydrotaea irritans (Fallen) (Diptera: Muscidae)

Summary Variation in the number of chromosomes was found in sheep headflies, ranging from 12 to 15 chromosomes. Of these, five pairs were common among all individuals. Among 9 larvae no males were identified.     

Occurrence of dihydromurexine (Imidazolepropionylcholine) in the hypobranchial gland ofThais (purpura)haemastoma

Riassunto Gli estratti metanolici di organo ipobranchiale diThais (purpura)haemastoma contengono cospicui quantitativi di un nuovo estere della colina, la diidromurexina o imidazolpropionilcolina. La base è localizzata esclusivamente nella striscia mediana giallastra dell'organo ipobranchiale, ove può raggiungere concentrazioni dell'ordine di 15–17 mg per g di tessuto fresco.

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Supported by grants from the Consiglio Nazionale delle Ricerche, Roma.     

Host-plant oligosaccharins in the honeydew ofSchizaphis graminum (Rondani) (Insecta,Aphididae)

Summary The honeydew of the aphidSchizaphis graminum (Rondani) contains hetero-oligosaccharides (mol. wt>2200 D) having neutral sugar and uronic acid compositions similar to the pectic substances of the host plant,Sorghum biocolor (L.) Moench. These oligosaccharides are pectic fragments which result from the depolymerization of pectic substances in the phloem by aphid salivary polysaccharases.     

Intergeneric interactions betweenEimeria separata (Apicomplexa) andNippostrongylus brasiliensis (Nematoda) in the rat

Summary Ova production inNippostrongylus brasiliensis infected rats was significantly greater than in rats singly infected with the helminth whenEimeria separata infections were introduced 4, 6 and 11 days postinoculation withN. brasiliensis. Patent periods were unaltered during concurrent infections. These results suggest that the presence ofE. separata affects helminth fecundity but does not increaseN. brasiliensis longevity as has been shown withE. nieschulzi.This study was supported by NIH MB RS Grant RRO8012-8.